Articles resistant to static buildup



United States Patent 3,262,807 ARTICLES RESISTANT T0 STATIC BUILDIUPMelvin D. Sterman and Louis M.- Minsk, Rochester, N .Y., assignors toEastman Kodak Company, Rochester, N.Y., a corporation of New Jersey NoDrawing. Original application June 12, 1962, Ser. No. 201,808, nowPatent No. 3,206,312, dated Sept. 14, 1965. Divided and this applicationMar. 8, 1965, Ser. No. 442,848

16 Claims. (Cl. 117-34) This application is a division of our copendingapplication Serial No. 201,808, filed June 12, 1962, now Patent No.3,206,312.

This invention relates to antistatic products comprising a supporthaving thereon a conducting layer containing a substantial proportion ofa water-soluble salt of a carboxy ester-lactone of an interpolymer ofalpha-betadicarboxylic acid (or anhydride) and a vinyl ester of acarboxylic acid.

In the manufacture and processing of a great many materials in film orfiber form, numerous problems are encountered due to the development ofstatic electricity. These problems are especially troublesome withphotographic products. In the case of photographic films, particularlythose coated with relatively high-speed photographic emulsion, it isnecessary to provide some means of retarding or eliminating theformation of static electricity. Unless this protection is provided,static discharges are prone to occur during the manufacture and use ofthe film, generating light which fogs the film and results in staticmarks upon development.

Certain conductive materials have been suggested for use as antistaticlayers in photographic products but many of them have disadvantages.They may exhibit such difiiculties as poor adhesion to the support; poormechanical properties which give brittle films which easily crack,flake, or peel; inadequate conductivity; or they may not be readilyremovable at some stage where this is desirable.

One object of our invention is to provide a new product having theproperty of preventing static build-up in manufacture and use. Anotherobject of our invention is to provide a material having antistaticproperties which also has other desirable properties. A further objectof our invention is to provide a material which in certain solventcombinations is coated directly upon film base or adheres satisfactorilyto film base by means of intermediate or sub layers which are readilyadherent to the film base. Other objects of our invention will appearherein.

We have found that the water-soluble salts of the carboxy ester-lactonesof the interpolymers of unsaturated alpha-beta-dicarboxylic acids ortheir anhydrides and vinyl carboxylic acid esters are useful inpreventing static build-up in photographic products, these saltsordinarily being alkali metal, or ammonium salts. The salts used may bethose of the polymers which result from the reaction of an aliphaticmonohydric hydroxy carboxylic acid and a monohydric alkanol containing1-12 carbon atoms with, for example, an interpolymer of vinyl acetateand maleic anhydride as described in US. Patent No. 3,007,901 of LouisM. Minsk. They also may be salts of carboxy ester-lactones prepared bythe partial hydrolysis of the essentially fully esterified polymers asdescribed by McNally and VanDyke in US. Patent Patented July 26, 19662,306,071, or, alternatively, they may be salts of carboxyester-lactones prepared directly by heating in the presence of a mineralacid a mixture consisting of a low-viscosity interpolymer of a vinylorganic acid ester and an unsaturated alpha-beta-dicarboxylic acid orits anhydride, water, and an aliphatic alcohol in such a ratio as toprovide polymer containing the desired carboxyl content. The usablecarboxy content of the carboxy ester-lactone polymers lies betweenapproximately 3.5 and 6 milliequivalents per gram of polymer, preferablybetween 4.5 and 5.5 milliequivalents per gram, with the optimal value atapproximately 5.0 milliequivalents per gram. The salt is convenientlyprepared by reacting the carboxylcontaining polymer with an alkalinematerial such as sodium carbonate, sodium hydroxide, ammonium hydroxide,or the like so that it is 25-98% (optionally 50-95%) neutralized by thealkali metal or ammonium ion as disclosed in pending US. applicationSerial No. 145,435.

The materials employed in preparing products in accordance with ourinvention may be prepared by the steps of (a) first heating to reactingtemperature, under acid conditions, a heteropolymer of a vinyl orisopropenyl organic acid ester and an unsaturatedalpha-beta-dicarboXylic acid with a mixture of a monohydric hydroxyacid, a monohydric alkanol, water and an inert solvent, to obtain aresinous carboxy ester-lactone having substantial proportions of each ofthe following recurring structural units:

wherein n represents an integer of 1-5, R represents an alkyl groupcontaining 1-12 carbon atoms, e.g., methyl,

ethyl, propyl, isopropyl, etc., or aphenyl-alkyl group lactone in anappropriate solvent such as acetone, adjusting the pH to 5-8 orpreferably 6-7 with an aqueous solution of a base whereby the inherentlyhydrophobic, unneutralized resinous carboxy ester-lactone essentiallyprepared is converted to the inherently hydrophilic salt of the resinouscarboxy ester-lactone wherein the original .lactone rings remainsubstantially intact, 25-98% optimally 50-95%) of the hydrogen of thecarboxyl groups having been replaced by the ammonium radical or alkalimetal atom. Suitable alkaline reagents for use in this latter stepinclude ammonium hydroxide and the alkali metal hydroxides of lithium,sodium, and potassium. In preparing the intermediate interpolymers usedin preparing these materials, the usual and preferred practice is toemploy the anhydride of the acid rather than the free dicarboxylic aciditself. It will be understood that where reference herein is made to theunsaturated alpha-betadicarboxylic acid, it is intended that thecorresponding anhydride be included.

Typical starting interpolymers in step-(a) referred to are thoseprepared from an unsaturated alpha-beta-dicarboxylic acid or itsanhydride, such as maleic acid,

' citraconic acid, dimethylmaleic acid, or anhydrides or 1-4 carbonalkyl esters thereof, fumaric acid, mesaconic acid, dimethylfumaric acidor 1-4 carbon alkyl esters thereof, or similar well-known dicarboxylicacid and vinyl organic acid ester such as vinyl acetate, vinylpropionate, vinyl benzoate or the like. The monohydric hydroxy acidspreferred are selected from the lactic acid series such as glycolicacid, lactic acid, hydroxybutyric acid and the like and the monohydrichydroxy alkanols include methanol, ethanol, propanol or the like up toand including the alcohols of 12 carbon atoms. The reaction in preparingthese products is carried out in the presence of a strong acid catalystsuch as a mineral acid having an acidity of the order of sulfuric acid.

The conducting salt'may be applied in accordance with our invention tothe support either alone or mixed with another polymeric material suchas gelatin or the like. In a photographic element it may be positionedin a great variety of locations to act as an antistatic backing layer,an anticurling layer, an antihalation layer, a conducting layer under,over, or between emulsion layers, or as an addend to the photographicemulsion. It may be incorporated into a photographically sensitiveproduct as an antistatic layer to protect the product during manufactureor use, or it may be applied to a developed material to protect thefinal product against dust accumulation.

Our conducting polymers are soluble in water but will tolerate largeamounts of organic water-soluble solvents. They may thus be appliedeither from water to a support supplied with a suitable subbing layer orthey may be applied from a mixture of water and organic solvents soadjusted as to have sufficient solvent action on the support to providegood adhesion of the conducting layer. With most film supports, acetonehas this effect of promoting adhesion. If, for instance, the support tobe employed is cellulose triacetate sheet, convenient compositions foruse in applying a layer directly to the base may be composed of 0.1-0.5%of the conducting polymeric salt dissolved in a solution of 25-70%acetone, 15-30% water,

and 0-60% methanol. In cases where the composition contains less than50% acetone, a surface-active agent might be used to give the desireddegree of wetting of thefilm. Similar coating solvent combinations alsogive satisfactory results on polystyrene and polycarbonate film bases.

While direct application of our conducting layers to a film support ispreferred for many applications, they may also be applied to supportbearing subbing layers. When a subbing layer is desired, any polymericmaterial which readily adheres to the film support used and to which theconducting polymeric salt will adhere is useful. One group of materialsthat works very effectively as subbing layers is the carboxyester-lactones of the interpolymers of maleic anhydride and vinylacetate. These may be coated, for example, onto the support from asolvent mixture of methylene chloride, acetone, and ethanol. Theconducting polymeric salts may then be overcoated from solutionscomposed of 10-100% water and -0% of methanol. Other polymeric materialssuch as gelatin, acrylates, or methacrylates, or copolymers of acrylatesand methacrylates with acrylic and alpha-substituted acrylic acids areuseful for subbing layers. Unlike most ionic polymers, the alkali metaland ammonium salts of the carboxy ester-lactones of the maleic anhydrideand vinyl acetate interpolymers, when cast into a support yield coatingswhich are clear, flexible and tough. Though hydrophilic in character,they do not become tacky at high relative humidities.

Our conducting polymeric salts are soluble in aqueous solutions and whencoated as described above remain soluble during drying and storing andused in photographic products are readily removable by aqueous solutionsduring processing. In certain applications where such solubility isundesirable, such as when coated in an anticurl layer or under or in anemulsion layer, our conducting polymeric salts may be rendered insolubleby the inclusion of a hardener which has the effect of insolubilizingcarboxyl-containing polymers. Such hardeners include aziridines such astriethylenemelamine, tris[l-(2-methylaziridinyl)Jphosphine oxide,hexa[1-(2- methylaziridinyl)]triphosphatriazine, ethylene bis[N,N-(l,2-propylene)urethane], hexamethylene 1,6 bis[3,3- ethylene urea] andmesitylene-2,4-6-tris[3,3-ethylene urea]; and epoxides such asbutane-1,4-diol bis(glycidyl ether), vinyl-cyclohexene dioxide,resorcinol diglycidyl ether, bis[2,3-epoxypropyl]propylamine, andbis[2,3- epoxypropyl]ethylmethyl-ammonium p-toluenesulfonate. In thisinsoluble form our conducting polymeric salts retain their excellentphysical properties and electrical conductivity. When our conductingpolymeric salts are used in admixture with other polymeric materials,such as with gelatin or the like, the conducting material shouldconstitute at least 15% of the solids to provide suitable antistaticprotection.

As mentioned earlier, other conducting polymers have shown numerousdisadvantages when used as antistatic layers. Some of these have beeninsolubilized with a hardener as described above and their physicalproperties were improved. Included among such conducting polymers are:(1) alkali metal and ammonium salts of other carboxy-containing polymerssuch as the terpolymers of vinyl phthalate, vinyl acetate and vinylalcohol, cellulose derivatives such as carboxymethyl cellulose and ethylcellulose phthalate, copolymers of acrylate esters and acrylic acid, ormethacrylate esters and methacrylic acid, polyacrylic acid,polymethacrylic acid, copolymers of acrylic acid and acrylamide,copolymers of maleic acid with styrene or ethylene, poly(vinyl carboxyester acetals and butals), alginic acid, copolymers of acrylic acid anditaconic acid, and polyitaconic acid, and (2) quaternary ammoniumpolymers such as poly-4-vinylpyridine quaternized with dimethylsulfateand poly-beta-dimethylaminoethyl methacrylate quarternized withdimethylsulfate.

In coating the conducting layers in preparing products in accordancewith our invention we have found that a useful range of pH of thecoating solution is from 4.5-8, and that a pH of approximately 6-7 ispreferred. The coating solutions may be employed in concentrationsranging from O.1-l0% of the conducting salt. Although solventcombination of acetone, methanol, and water have been found to beparticularly useful in coating directly onto the film base, and coatingsolutions composed of water and methanol have been found useful forcoating onto subbing layers, other solvent combinations of evaporableliquids may be employed to give coatings with good adhesion and goodcohesive properties. Optionally, surfactants which function as a coatingaid may be included in the coating solutions. A wetting agent such asp-tert.

octylphenoxyethoxyethyl sodium sulfonate is eminently suitable. Insteadof this surface-active agent, others which are commonly recognized assuch may impart the desired wetting properties to the coatingcomposition. For instance, disodium N(carbo-p-tert.-octylphenoxypentaethoxy)-glutamate as described in Knoxet al. application Serial No. 600,679, now Patent No. 3,038,804, isuseful for this purpose.

The following examples illustrate specific embodiments of our inventionbut should not be regarded as limiting.

Example 1 Cellulose triacetate film support was coated with a subbinglayer by means of a solution at 0.2% concentration of a carboxy butylester-lactone of maleic anhydride-vinyl acetate interpolymerprepared asdescribed in US. Patent No. 3,007,901 by modifying maleicanhydride-vinyl acetate interpolymer with glycolic .acid and n-butylalcohol. The solvent used was composed of 20 parts of methylenechloride, 55 parts of acetone, and 25 parts of ethanol. The coatingcomposition was applied to the film support by the bead method ofapplication. The thus subbed support was overcoated with a solution ofthe sodium salt of the carboxy butyl ester-lactone of maleicanhydride-vinyl [acetate interp olymer at 0.5% concentration using asthe solvent a mixture of 60 parts of water and 40 parts of methanol. ThepH of the solution was adjusted to 6. The thus formed product was foundto have a surface resistivity of ohms per square inch at 50% relativehumidity. The [antistatic backing exhibited good adhesion, good abrasionresistance, good ferrotyping properties, and both the antistatic backingand the sub layer were completely removable in alkaline photographicdeveloper solutions.

Example 2 Cellulose triacetate film base support was coated with a sublayer by means of a solution of a copolymer of methacrylic acid andmethyl acrylate at 0.2% concentration in a solvent consisting of 20parts of methylene chloride, 55 parts of acetone, and 25 parts ofethanol. The subbed support was overcoated with an aqueous solution ofthe sodium salt of the carboxy butyl ester-lacetone of maleic:anhydride-vinyl acetate interpolymer at a concentration of 0.5% havinga pH of 6. The resulting coatings were found to have a surfaceresistivity of 10 ohms per square inch at 50% relative humidity. Thecoating exhibited good adhesion to the support, and both the antistaticbacking and the sub-layer were completely removed in photographicdeveloper solution.

Example 3 Cellulose triacetate film support was coated with a solutionof the following composition: 0.2% of the sodium salt of the carboxybutyl ester-lactone obtained from glyoolic acid, n-butyl alcohol, and amaleic anhydridevinyl acetate interpolymer dissolved in a mixed solventcomposed of 20% water, 50% methanol, and 29.8% acetone. The pH of thesolution was adjusted to about 6. The solution was coated at a hopperand drum temperature of 100 F., and the coating was dried above 180 F.The coating bad a surface resistivity of less than 10 ohms per squareinch at 50% relative humidity and exhibited excellent adhesion to thesupport, good :abrasion resistance, and coefiicient of friction, and wascom-- pletely removable in alkaline deve-lo er solutions.

Example 4 Starting with an aqueous dope of the sodium salt of thecarboxy butyl ester-lactone of maleic anhydride-vinyl acetateinterpolymer at 10% solids, a coating solution was prepared having thefollowing composition: 5% of the conducting material, 0.15% oftriethylenemelamine, and 0.05% of p-tert.-octylphenoxyethoxyethyl sodiumsullfonate, all in water; the IPH of the solution was adjusted to 7. Acellulose triacetate film base as coated with a mixture of gelatin andcellulose nitrate in acetone-water solvent. This film support was thencoated with the solution of conducting material by means of an extrusionhopper and dried by blowing hot air over the surface of the coating.This support was coated on the same side with a gelatin-silver halidephotographic emulsion and then with a gelatin overcoat. A control wasprepared in which the cellulose tri acetate film base was coated withthe gelatin-cellulose nitrate subbing layer and with the emulsion andgelatin overcoat but without the conducting material. Strips of bothfilms were aged for seven days at 7701*. and 50% relative humidity. Theappearance of each was excellent and each coating exhibited good dry andwet adhesion to the support. The sensitometric characteristics of theemulsion coated over the conducting material were equal to those for thecontrol coating. However, whereas the emulsion surface resistivity at50% relative humidity of the control coating in ohms per square inch was15 10 the emulsion surface resistivity of the product in which theconducting coating was used wa 0.013 X10 Camera static tests performedon the coatings showed that the product lembodying an application of theinvention was much less susceptible to static markings than the controlcoating.

In this test, five different 35 mm. cameras were used at 15% and 30%relative humidity. Also, the emulsion of the product using theantistatic material in accordance with our invention showed no edgestatic markings as a result of static electricity created duringperforation of the film product. The control product was particularlyedge marked during this process.

Example 5 The same antistatic coating composition as given in Example 4was coated onto poly(ethy-lene terephthal-ate) film base, having ahydrosol coating and a gelatin overcoat, by means of a coating machinehaving an extrusion hopper and the coating was dried by blowing hot airthereon. Samples of the resulting conducting support were overcoatedwith different gelatin-silver halide photographic emulsions. Controlproducts. were also prepared without the conducting coating. Strips ofthe conducting support, the products with the conducting layerovercoated with photosensitized emulsion, and the controls were all agedfor seven days at 77 F. and 50% relative humidity. The appearance ofeach coating was excellent and good dry and wet adhesion was exhibitedin each. It was found that the products in which the antistatic layerwas overcoated with photosensitive emulsion when physically tested wereas good as or better than the controls. The surface resistivity of thesupport coated with the antistatic layer was 0.0024 10 ohms per squareinch. When emulsion coated the surface resistivity ranged from 0.046 10to 0.2x 10 The surface resistivity values for the emulsion coatedcontrols ranged from 13.0)(10 to 480x10 All values were Example 6Starting with the aqueous dope described in Example 4, a coatingsolution was prepared consisting of an aqueous solution containing 5% ofthe sodium salt of the car boxy butyl ester-lactone of maleicanhydride-vinyl acetate interpolymer, 0.15% ofhexa[l-(2-methylaziridinyl)] triphosphatriazine as a hardener thereinand 0.05% of rp-tert.-octylphenoxyethoxyethyl sodium sulfonate. The pHwas adjusted to 7.' ,This solution was coated onto a gel-subbedcellulose triacet-ate film support in the manner described in Example 4.This support was then overcoated with a gelatin silver halidephotographic emulsion. A cont-r01 product was prepared of (like typeexcept that the antistatic layer was omitted. Strips of the antistaticcoated film base and the two emulsion coated products were aged forseven days at 77 F. and 50% relative humidity. The coating wereexcellent and all exhibited good dry and wet adhesion. Thorough physicaltesting of the coatings indicated that the products having the staticcoatings were as good as or better than those of the control. The filmbase coated with the antistatic coating had a surface resistivity of0.0023 X 10 ohms per square inch. The surface resistivity of the productutilizing the antistatic coating in accordance with our invention was0.2 10 ohms per square inch and that of the control product as 59x10These values were measured at 50% relative humidity.

Example 7 Employing the antistatic coating dope of Example 6 mixed with12% by weight of Titanox as a filler based on the sodium salt of thecarboxy butyl-lactone, a coating was applied from a hopper to thereverse side of paper stock coated with a photo-sensitive emulsion atsuch a rate as to provide adequate anticurl protection. The resistivityof this coating after aging for a week was 8.6 10' ohms per square inchat 42% relative humidity. A similar anticurl backing prepared fromgelatin had a resistivity of approximately 1 10 ohms per square inch.

This coating was repeated on polyethylene-coated paper stock. Theresistivity after aging for one week was 8.-1 10 ohms per square inch.

Example 8 Starting with the aqueous dope described in Example 4, acoating solution was prepared consisting of an aqueous solutioncontaining of the sodium salt of carboxy 'butyl ester-lactone of maleicanhydride-vinyl acetate interpolymer, 0.15% oftris[I-(Z-methylaziridinyl)]phosphine oxide as a hardener therein and0.05% of p-tert.- octylphenoxyethoxyethyl sodium sulfonate. The pH ofthe solution was adjusted to 7 and the solution was coated ontogel-subbed triacetate film support as described in Example 4. Thissupport was then overcoated with a photographic emulsion and wascompared with a like product containing no antistatic layer as acontrol. The electrical surface resistivity of the film having anantistatic layer in accordance with the invention was 0.2)( ohms persquare inch, whereas the control product had a surface resistivity of 7710 ohms per square inch. The resistivity was measured at 50% relativehumidity.

Example 9 A coating solution identical to that described in thepreceding example was prepared and coated on both sides of a gel-subbedcellulose acetate butyrate film base. This film base was coated on bothsides with a photographic silver halide emulsion and a control productwas prepared being identical except that the antistatic coatings wereomitted. The two products were aged for seven days at 77 F. and 50%relative humidity. The

coatings in each case had good appearance and excellent wet and dryadhesion. The surface resistivity of the film which had the antistaticcoating in accordance with our invention was 0002x10 ohms per squareinch, while that of the control film was 7 10 ohms per square inch, allvalues having been measured at 50% Example 10 A. A cellulose triacetatefilm support was coated with an antihalation layer in the form of a dyedgelatin layer at the rate of 1750 mg. of gelatin per square foot. Thislayer was then overcoated with a layer of the sodium salt of carboxybutyl ester-lactone of the interpolymer of maleic anhydride-vinylacetate at the rate of 0.150 grams per square foot.

B. A silver bromoiodide-gelatin photographic emulsion on a cellulosetriacetate film support was overcoated Resistivity (X10 ohms/sq. in.)

Gelatin layer alone 680 Gelatin layer overcoated with antistatic layer,Emulsion layer alone (480 mg. Ag and 525 mg.

gel'atin/ sq. ft.) 20,000 Emulsion layer overcoated with antistaticlayer 1,000

Example 11 An antistatic layer composed of a mixture of sodium salt ofcarboxy butyl ester-lactone of the interpolymer of maleicanhydride-vinyl acetate, hexamethylene 1,6 bis[3,3-ethylene urea] as ahardener, and a gelatin was coated onto a cellulose triacetate filmsupport, which layer was overcoated with a silver bromoiodide-gelatinphotographic emulsion. The antistatic layer was composed of equal partsof gelatin and the conducting sodium salt and 3% hardener based on theweight of the latter. A similar product was prepared but with theantistatic layer omitted. Tests were made of these two products at 20%relative humidity and 70 F. to determine surface electrical resistivity.The results obtained were as follows:

Silver bromoiodide-gelatin emulsion coated over a layer containing 114mg. gelatin-H14 mg. antistatic salt Example 12 Sodium salt of carboxybutyl ester-lactone of the interpolymer of maleic anhydride-vinylacetate was added to a silver bromoiodide-gelatin photographic emulsionin an amount 16% of the the weight of the gelatin present. A layer ofthis emulsion-was applied on a cellulose triacetate film support and agelatin overcoat was applied thereto. Determination of the surfaceresistivity of this product compared with a photographic film resultingfrom applying a layer of conventional silver bromoiodidegelatinphotographic emulsion on cellulose triacetate film support gave thefollowing results at 2% relative humidity and 70 F.:

Resistivity 10 ohms/sq. in.) Emulsion layer (750 mg. Ag and 1440 mg.gelatin/sq. ft.) 1,340 Emulsion layer+2l5 mg. antistatic salt/sq. ft.

overcoated with a gelatin layer (83 mg. gelatin/ sq. ft.) 104 Example 13A photographic negative was dip coated in a three percent aqueoussolution of the sodium salt of the carboxy butyl ester-lactone of thepresent invention which had been adjusted to a pH of 7 and contained0.05 of iso-octylphenoxypolyethoxyethanol to improve flow properties.After drying in a current of warm air, the emulsion side of the negativehad a surface resistivity of 2.0+10 ohms per square inch and the pelloidside had a surface resistivity of 2.6)(10 ohms per square inch at 50%relative humidity. Both sides of a control which '20 hours.

salts in the usual manner.

3 Was not coated had surface resistivity of 4 10 ohms per square inch.

While the conducting salts of the previous examples have been those ofcarboxy .butyl ester-lactones prepared from the vinyl acetate-maleicanhydride interpolymer, glycolic acid, and n-butyl alcohol, similarconducting layers may be obtained with the salts of similar carboxyester-lactones prepared from other polymers, hydroxy acids and alcoholsas described in US. Patent No. 3,007,901 of Louis M. Minsk.

Other related carboxy ester-lactone polymers which give salts thatprovide equally effective conducting layers have been made in thefollowing manner. A mixture of 200 g. of vinyl acetate-maleic anhydrideinterpolymer, 1 :.23 (the inherent viscosity of the vinylacetate-m-aleic anhydride intermediate used here should be no more thanabout 0.25 measured in acetone solution comprising 0.25 grams of polymerper 100 ml. of solution to inhibit serious cross-linking), 600 ml; ofdistilled water, and 70 ml, of n4butyl alcohol were stirred untilsolution occurred. To this was added 68 ml. of concentrated sulfuricacid, and the solution was heated on a steam bath for approximatelyDuring this time the carboxy butyl ester lactone separated from solutionas a solid. This was transferred to a sigma-bladed mixer and milled inrepeated changes of water to harden and break up the polymer and reducethe acidity. The last traces of acid were removed by washing severaltimes with rapid stirring and filtering the sample after each wash.After drying in a 40 oven, 150 g. of polymer were obtained which had acarboxyl content of 5.18 millequivalents per gram of polymer. Carboxyester lactones of higher or lower carboxyl content are obtained byemploying smaller or larger amounts of alcohol in the reaction. Thesecarboxy-containing polymers are converted to their alkali metal orammonium The above-described polymer was converted to its sodium saltand coated on paper from a five percent aqueous solution containingthree percent based on the weight of the polymer of the aziridinehardener, hexamethylene-1,6-bis[3,3-ethylene urea], and having a pH of 7at the rate of 2.5 grams per square meter. After hardening for threedays at room temperature, the coating had a resistivity of 4x10 ohms persquare inch at relative humidity,

The usefulness of carboxy ester-lactone polymers prepared as describedin the preceding paragraph depends upon the inherent viscosity of theinterpolymer used as the intermediate in its preparation. It has beenfound that this alpha-beta-unsaturated dicarbo-xylic acid-vinyl esterinterpolymer intermediate should have an inherent viscosity of notexceeding approximately 0.25 measured in acetone solution comprising0.25 gram of polymer per 100 ml. of solution for making a desirableproduct in which serious cross-linking is avoided. The making of theseuseful carboxy ester lactones by reacting a low viscosity intermediatewith a lower alkanol under aqueous acid conditions is not our inventionbut is the invention of Louis M. Minsk and Edward P. Abel described andclaimed in their application Serial No. 304,676.

We claim:

1. An article resistant to static build-up comprising a support havingthereon a coating composed of 15-100% of a water-soluble salt of acarboxy ester-lactone of an interpolymer of an unsaturated alphabeta-dicarboxylic acid and a vinyl ester of a carboxylic acid, whichsalt is -98% neutralized.

2. An article resistant to static build-up comprising a support and acoating composed of 15100% of a watersoluble salt of a carboxyester-lactone of an interpolymer of maleic anhydride and vinyl acetate,which salt is 25- 98% neutralized.

3. An article resistant to static Ibuild-up comprising a support and acoating composed of 15-100% of a sodium salt of a carboxy ester-lactoneof an interpolymer of maleic anhydride and vinyl acetate, which salt is25-98% neutralized,

4. An article resistant to static build-up comprising a support and acoating composed of at least 15% of a water-soluble salt of a carboxyester-lactone of an interpolymer of an unsaturated alphabeta-dicarboxylic acid and a vinyl ester of a carboxylic acid, whichsalt is 25- 98% neutralized, substantially the remainder of the coatingbeing gelatin.

5. An article resistant to static build-up comprising a support, asubbing coating thereover and upon the subbing coating a coatingcompose-d of 15-100% of a water-soluble salt of a carboxy ester-lactoneof an interpolymer of an unsaturated alpha-beta-dicarboxylic acid and avinyl ester of a canboxylic acid, which salt is 25-98% neutralized.

6. An article resistant to static build-up comprising a support havingdirectly thereon a subbing coating composed of a carboxy ester-lactoneof an interpolymer of an unsaturated alpha-beta-dicanboxylic acid and avinyl ester of a carboxy acid and thereover a coating composed of awater-soluble salt of a carboxy ester-lactone of an interpolymer of anunsaturated alpha-beta-dicar-boxylic acid and a vinyl ester of a carboxyacid, which salt is 25-98% neutralized.

7. An article resistant to static build-up comprising a support and acoating thereon composed of an alkali metal salt of a carboxyester-lactone of an interpolymer of an unsaturatedalpha-beta-dicarboxylic acid and a vinyl ester of a carboxy acid, whichsalt is 25-98% neutralized said coating containing an insolubilizingmeans therefor.

8. An article resistant to static build-up comprising a cellulosetriacetate support and a coating thereon composed of a water-solublesalt of a carboxy ester-lactone of an interpolymer of an unsaturatedalpha-beta-dicarboxylic acid and a vinyl ester of a carboxy acid, whichsalt is 25-98% neutralized.

9. An article resistant to static build-up comprising a cellulosetriacetate support layer having directly thereon a subbing layercomposed of a copolymer of methacrylic acid and methacrylate andthereover a layer composed of an alkali metal salt of a carboxyester-lactone of an interpolymer of an unsaturatedalpha-'beta-dicarboxylic acid and a vinyl ester of a carboxylic acid,which salt is 25- 98% neutralized.

10. An article resistant to static build-up comprising a cellulosetriacetate support layer and a layer composed of a water-soluble salt ofa carboxy ester-lactone of an interpolymer of an unsaturatedalpha-beta-dicarboxylic acid and a vinyl ester of a carboxylic acid,which salt is 25- 98% neutralized, substantially the remainder of thelayer being gelatin.

11. An article resistant to static build-up comprising a support and acoating thereon composed of a water-soluble salt of a carboxyester-lactone of an interpolymer of an unsaturatedalphaabeta-dicarboxylic acid and a vinyl ester of a carboxy acid, whichsalt is 25-98% neutralized said coating containing therein a substantialamount of titanium dioxide.

12. An article resistant to static build-up comprising a support and acoating thereon composed of a water-soluble salt of a carboxyester-lactone of an interpolymer of an unsaturatedalpha-beta-dicarboxylic acid and a vinyl ester of a carboxy acid, whichsalt is 25-98% neutralized and therein as a hardener hexa[1-(2-methylaziridinyl)] triphosph-atriazine.

13. An article resistant to static build-up comprising a celluloseacetate butyrate support and a coating thereon composed of awater-soluble salt of a carboxy ester-lactone of an inter-polymer of anunsaturated alpha-betadicarboxylic acid and a vinyl ester of a carboxyacid, which salt is 25-98% neutralized.

14. An article resistant to static build-up comprising a support and acoating thereon composed of a water-soluble salt of a carboxyester-lactone of an interpolymer of an unsaturatedalphaabeta-dicarboxylic acid and a vinyl ester of a carboxy acid, Whichsalt is 25-98% neutralized and therein as a hardener polyepoxide.

15. An article resistant to static build-up composed of a support havinga polyethylene terephthalate surface and a coating thereon composed of awater-soluble salt of a carboxy ester-lactone of an interpolymer of anunsaturated alpha-beta-dicarboxylic acid and a vinyl ester of a carboxyacid said salt being 25-98% neutralized.

16. An article resistant to static build-up composed of a support havinga polyolefin surface and a coating thereon composed of a water-solublesalt of a carboxy esterlactone of an interpolymer of an unsaturatedalpha-betadicanboxylic acid and a vinyl ester of a carboxy acid saidsalt being 2598% neutralized.

References Cited by the Examiner UNITED STATES PATENTS MURRAY KATZ,Primary Examiner.

RICHARD D. NEVIUS, A. H. ROSENSTEIN,

Assistant Examiners.

1. AN ARTICLE RESISTANT TO STATIC BUILD-UP COMPRISING A SUPPORT HAVINGTHEREON A COATING COMPOSED OF 15-100% OF A WATER-SOLUBLE SALT OF ACARBOXY ESTER-LACTONER OF AN INTERPOLYMER OF AN UNSATURATEDALPHA-BETA-DICARBOXYLIC ACID AND A VINLY ESTER OF A CARBOXYLIC ACID,WHICH SALT IS 25-98% NEUTRALIZED.